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Lucene example source code file (QueryWrapperFilter.java)

This example Lucene source code file (QueryWrapperFilter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

docidset, docidset, docidsetiterator, filter, indexreader, io, ioexception, ioexception, override, override, query, querywrapperfilter, querywrapperfilter, string, weight

The Lucene QueryWrapperFilter.java source code

package org.apache.lucene.search;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;


import org.apache.lucene.index.IndexReader;

/** 
 * Constrains search results to only match those which also match a provided
 * query.  
 *
 * <p> This could be used, for example, with a {@link TermRangeQuery} on a suitably
 * formatted date field to implement date filtering.  One could re-use a single
 * QueryFilter that matches, e.g., only documents modified within the last
 * week.  The QueryFilter and TermRangeQuery would only need to be reconstructed
 * once per day.
 */
public class QueryWrapperFilter extends Filter {
  private Query query;

  /** Constructs a filter which only matches documents matching
   * <code>query.
   */
  public QueryWrapperFilter(Query query) {
    this.query = query;
  }

  @Override
  public DocIdSet getDocIdSet(final IndexReader reader) throws IOException {
    final Weight weight = new IndexSearcher(reader).createNormalizedWeight(query);
    return new DocIdSet() {
      @Override
      public DocIdSetIterator iterator() throws IOException {
        return weight.scorer(reader, true, false);
      }
      @Override
      public boolean isCacheable() { return false; }
    };
  }

  @Override
  public String toString() {
    return "QueryWrapperFilter(" + query + ")";
  }

  @Override
  public boolean equals(Object o) {
    if (!(o instanceof QueryWrapperFilter))
      return false;
    return this.query.equals(((QueryWrapperFilter)o).query);
  }

  @Override
  public int hashCode() {
    return query.hashCode() ^ 0x923F64B9;
  }
}

Other Lucene examples (source code examples)

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